The floor pan of a vehicle provides a floor in the passenger compartment. The floor pan extends between the rocker panel assemblies and the rear rails. The floor pan is also supported by cross-members below the floor pan. Vehicles are tested for side impact protection in a test identified as FMVSS No. 214 “Side Impact Rigid Pole Test” The test requires impacting a rigid pole 254 mm in diameter with the side of a vehicle at a speed of 32.2 km/h. One potential problem is indicated if the floor pan separates from vehicle structures such as an adjacent rocker assembly, a rear rail or a kick-up cross member.
Floor pan separation may be attributed to spot weld failure. Spot welds in automotive vehicles are subjected to complex loading during a collision event. Shear loading of spot welds occurs as a result of relative displacement or in-plane rotation of adjacent sheets. Tensile loading occurs as a result of separation forces applied between adjacent sheets in a direction normal to the adjacent sheets.
Lower gauge sheet metal is increasingly being used in vehicles to reduce weight and increase fuel economy. With the use of lower gauge sheet metal, spot weld strength may be inadequate to prevent floor pan separation in a side impact collision depending upon the specific design of the vehicle structure.
This disclosure is directed to the above problems and other problems as summarized below.